Now, however, we can, by DNA sequencing, look at DNA directly, and with some fancy statistical footwork, get an idea of which genes have changed in frequency so fast that they must have been due to positive natural selection. That’s the subject of a new paper in Science by Yair Field et al. (reference and free download below). The authors conclude that several traits, including lactose tolerance, hair and eye color, and parts of the immune system, as well as height, have evolved within the last 2,000 years.

Other genes that might have changed during that period include those for infant head circumference, insulin levels, birth weight, and female hip size.